Solar cells generate electric energy using the photovoltaic effect of a p-n junction which converts photons of sunlight into electricity. In the solar cell, front and rear electrodes are formed on upper and lower surfaces of a semiconductor wafer or substrate with the p-n junction, respectively. Then, the photovoltaic effect of the p-n junction is induced by sunlight entering the semiconductor wafer and electrons generated by the photovoltaic effect of the p-n junction provide electric current to the outside through the electrodes. The electrodes of the solar cell are formed on the wafer by applying, patterning, and baking a composition for electrodes.
Continuous reduction in emitter thickness for improvement of solar cell efficiency can cause shunting which can deteriorate solar cell performance. In addition, a solar cell has been gradually increased in area to achieve high efficiency. In this case, however, there can be a problem of efficiency deterioration due to increase in contact resistance of the solar cell.
Solar cells are connected to each other by a ribbon to constitute a solar cell battery. In this case, low adhesion between electrodes and the ribbon can cause large serial resistance and deterioration in conversion efficiency.
The inventor of the present invention developed a solar cell that provides necessary electrical properties such as conversion efficiency and physical properties such as adhesive strength.